Turn rate control system



NOV- 19, 1963 J. Bl-:NrKowsKY a-rAL 3,111,105

TURNRATE CONTROL SYSTEM Filed April 17 United States Patent C 3,111,105TURN RATE CONTROL SYSTEM Jerome Bentkowsky, Charlottesville, Va., JosephH.

Chadwick, Jr., Amityville, N.Y., and Virgel E. Williams,Charlottesville, Va., assignors to Sperry Rand Corporation, Great Neck,N.Y., a corporation of Delaware Filed Apr. 17, 1962, Ser. No. 188,115 16Claims. (Cl. 114-144) This invention relates to a turn rate rcontrolsystem for navigable craft. More particularly, the invention converns amanually openated steering system for craft of the marine .type havingrudders where no limits are imposed on the travel of the rudder duringturns.

`In the improved system, the turn order input means to the servo meansconnected to operate the rudder determines the turn rate of the craftrather than the rudder angle. Turn orders are derived from an ordersynchro that is controlled by ia manually movable member in the form ofa helm control stick. The movement of the stick from a null position isobserved by an operating helmsman on a turn rate indicator included on adisplay panel. The stick under control of the helmsman is operativelyconnected to the movable part of the turn rate indicator to designatethe ordered turn rate. The stick of .the turn order input means is alsooperatively connected to the order synchro to provide an outputdepending on its movement yfrom a null position.

The improved steering syste-rn controls the turn rate of the craft bythe provision of an input to the rudder servo means that is inopposition to the output of the synchro of the turn order input means.The means opposing the turn order means includes means providing anoutput depending on the actual rate of turn of the craft. The turningmaneuver of the craft about its yaiw axis is observed by the helmsman ona heading indicator provided on the display panel of the system withrelatively movable scale and pointer parts. Where for instance the scaleof the heading indicator is a compass card and the pointer is a fixedlubber line or index on the panel, the card appears to move withrelation to the line las the craft turns lfrom its initial heading tothe ordered heading.

The azimuth direction in a turn at which it is necessary =for thehelmsman to return the stick or movable member to its null position tocheck the rudder so that the craft moves to the ordered heading smoothlyis indicated on the display panel by the relative displacement betweenthe index of the heading indicator and a movable element with a partreadable on the compass card of the heading indicator. Another part oflthe movable element of the display panel is read by the helmsman withrelation to the parts of the turn rate indicator of the system tocompare the ordered turn rate to the actual turn rate and enable thesystem to utilize the full range of the helm stick at all speeds of thecraft. The operation of the movable element of the panel common to theheading and turn indicators is dependent on the rate that the craft isactually turning divided by its actual speed. This ratio is equivalentto the reciprocal of the turning radius of the craft and isapproximately proportional to the actual turn rate of the craft dividedby the maximum turn rate obtainable for va particular craft speed. Thisenables the system to operate to turn the craft at a rate below itsmaximum .turn rate for a particular craft speed and accordingly obviatethe need of rudder angle limits. The heading error or turn pull-outheading observed on the display panel of the system with relation to thescale of the heading indicator is the angular dilference between theordered heading and the actual heading of the craft at which it isnecessary to null the ice order input to the rudder. This error isapproximately proportional to the reciprocal of the turn radius of thecraft at its operating speed as provided as an input to operate themovable element common to the heading and turn indicators of the displaypanel. As the system enables the helmsman to observe the exact turncut-off heading point, heading changes are effected accurately andsmoothly through the single initiating and single return movements ofthe stick or manually movable member.

The primary object of the present invention is to provide a system forsteering a craft that only requires two operations of the helmsman tocomplete an ordered turn accurately and smoothly without overshooting.

A feature of the invention is provided by the included display panelwith turn rate and heading indicators and with a movable element with apart readable on the scale or compass card of the heading indicator anda part readable with relation to the parts of the turn indicator.

Other objects, features and structural details of the invention will be.apparent from the following description with relation to .theaccompanying drawing showing a schematic diagram of the relatedcomponents of our improved turn `control system.

The improved turn control system shown has particular utility inresponse to helm commands to maneuver a craft such as a submarine orsurface marine craft by direction of its rudder lfrom one heading toanother heading. Orders to the system from the helm represent turn raterather than rudder angle as utilized in conventional steering systems.The orders given the rudder in the improved system bring Ithe craftquickly, accurately and smoothly to an ordered turn rate and maneuverthe craft in the turn to its ordered heading yWithout overshooting.

As shown, the craft component utilized in the system is provided byarudder 10 that is driven by servo means operable to change the headingof the craft. The servo means shown includes a heading output servo 11and a steering engine 12 connected to the rudder 10l through suitablegears and shafting. Servo 11 further includes a mixer 13 for combiningthe control outputs of the system whose output lead 14 is connected to amotor 15 by way of amplier 1'6 and lead 17. The output shaft 18 of motor15 drives the rotor of a suitable transmitter or synchro 19 that isenergized from a suitable source of electrical power indicated at 20.Lead 21 connects the driving synchro l19 to the steering engine 12 tocontrol its operation. Servo 11 further includes a `repeatback outputfor the drive motor 15 in the arrangement shown in the form of anelectrical transmitter or synchro 22 whose rotor is positioned inaccordance with the motor output shaft 18. As shot/vn, synchro 22 isenergized from the power source 20 and is connected as an input to mixer13 by way of lead 23.

Turn orders for lthe system are derived from an order transmitter orsynchro 24 that is also energized from the power source 20. The meansfor ordering a turn rate input glo to the servo 11 of the systemincludes synchro 24 that is connected to mixer 13 by way of lead 25 anda manually movable member or helm control stick 26 that is operativelyconnected to the rotor of the synchro 24 through suitable shaft 27. Asshown, the member or stick 26 is pivota-bly mounted on the instrumentpanel 23 of the craft and is biased to `a null position by a pair ofcentering springs 29, 30. The output of synchro 24 depends on themovement of the stick or member 26 from its null position Iby thehelmsman in the direction of the arrow designated yas a turn to port :orin the direction of the arrow designated 'as `a turn to starboard. 'Ihemovement of the stick 26 is observed by the .operating helmsman on a,turn rate indicator 31 located on a display panel 32 also located onthe instrument panel of the craft. In-

dicator 31 includes relatively movable scale and Ipointer parts and inthe arrangement shown a movable pointer 33 operatively connected tostickl26 through shaft 34 to connecting shaft 27 is moved with respectto a ixed rate of turn scale 35 to provide a turn rate input glio tomixer 113 requiring the craft to` turn to port at the indicated rate. Incommanding the turn, .the movement of the stick or manually movablemember 26 under control of the helmsman is read on .the turn rateindicator 31 of the display panel 32.

The display panel component 3.2v of the improved system further includesa heading indicator 36 having relatively movable scale land pointerparts. The scale part of heading indicator 36, shown is -a compass card37 and the pointer partis a fixed index 38. In turns, the card 37appears to Inlove with relation to the fixed index 38 although -thehelmsman reading the indicator 36 actually moves with the index 38around the stabilized card 37 as the craft moves. As read on thisindicator, the craft is shown to be on a northerly or zero degreeheading.

The directional stabilization required for the card 37 in the type ofheading indicator 36 included in the display panel component 32 of Itheimproved system is provided by a suitabledirectional reference 39 in theform of a gyro compass whose follow-up ring 40 is positioned by anazimuth drive motor 41. As shown, the card 37 of the indicator 36 isslaved to the `shaft 42 of the motor 41 by way yof therotor of a compasssynchro 44 energized from power source 20. The synchro 44 in thearrangement shown is connected to the receiving synchro 45 by way oflead46, and the rotor of the synchro 45 is connected to the card 37 by meansof shaft 47. The card 37 is accordingly directionally stabilized by thereference 39 so that it remains fixed with respect -to the index orpointer `38 as this element of Vthe heading indicator moves with thehelmsman with respect to the card 37 as the craft yaws or turns from oneheading to another.

As further shown in the drawing, the display panel 32 of the improvedsystem also includes an ordered heading indicator 48 in the form of athree digit counter with representative directional indiciacorresponding to the indicia includedon the scale 37 of the headingindicator 36. A headingV setter crank 49` connected to indicator 48y byshaft 50 is operated lby thelhelrnsrnan to indicate the heading orderedfor the craft `at the completion of the turn. The heading to which thehelmsman has been ordered to bring the craft is set inl before the stick26 is moved. As shown in FIG. 1, the heading ordered for the craft atthe completion of this described turn is 336 degrees as represented onthe ordered heading indicator 48l on the display panel` 32.

In the operation of lthe improved system, the output inl/ of Athecraftsk turn rate :order means from synchro 24 is opposed at the mixer13 by `a-means providing an output depending on the actual turn rate of:the craft. Initial movement of the stick 2 6 in lthe direction of theport arrow in the drawing with corresponding movement of the rateindicator pointer 33 to port results in an ordered outputgbo from thesynchro24 to operate the servo means 11v to move the rudder 10l andstartthe illustrative maneuver herein described. As the craft starts to turn,the actual turnrate output means providesyan output that opposes theyorder rate output r/U. As shown in FIG. 1, the opposing output meansincludes a turn rate servo or computer 5,1- with a follow-upl motor 52driven by the output of a data transmission system including the compasssynchro 44 and a repeater synchro 54 connected to synchro 44 by lead-53.The motor 52 receives the output ofthe repeater synchro 54 byway of lead56, amplifier 57 and'lead l58 and drives the` rotor of the notedsynchroto nulllthrough thevconnecting shaft 59. Motor 52 is accordinglyoperated at a rate that is dependent on the actual rate that the craftis moving about its yaw axis. As Shawls, the. mQtQr. 5.211180 dnves@generator 60 by Way Qf shaft 61,v the generator including an excitingwinding energized from source 20 and an output winding connected to the-mixer 13 by way of lead 73, dividing means rb/ V indicated at 72, andlead 78 to lead 62. To maintain sutiicient rudder to get the craft intothe turn without requiring rudder limits, the output gl/U included inthe system by the helmsman is initially greater than the cornJ binedoutputs of the rate generator 60 and the repeatback synchro 22. As theturn proceeds, the crafts turn rate 1,2/ increases with relation to thefixed output order 300 so that less and less lrudder is required and theoutput of repeatback slowly approaches null with the rudder streamlined.After the stick input to is removed from thev system as hereafterdescribed, the rudder reverses direction under control of the Output 1,0only to slow the turn rate of the craft lto null `as the ordered headingof the craft is reached. Here as the turn rate r/f decreases, the outputof the lrepeatback synchro 22 also decreases so that when the vcraftarrives `at the heading ordered the rudder is also positioned in astreamlined condition.

To enable -the helmsman to compare the ordered and actual turn rateinputs to the servo. means 11, the display panel I32 further includes anelement 65 with a pointer part y66 readable on the turn rate indicator31. As shown, elemen-t 65 is a vertical arm that is supported by anactuating piece `67 of a turn rate meter A68 to move across Ithe face ofthe panel v32 in the directions indicated by the horizontal arrows 69, 70. With no input to the meter 68, the piece 67 is biased so that theelement 65 and pointer part 66 assume respective vertical positions atthe center of the panel where the pointer part `66 is at the zero scalereading `of the turn rate indicator 41. As the system operates and faninput commanding a turn to port is fed to the meter 68, the pointer part`66 of the panel indicator moves in the direction indicated by Athearrow 70 following the movement to the pointer 33 of the turn indicator31 under control of the helmsman. This enables the helmsman to comparethe relative positions ofthek respective pointer parts 33 and 66 withrespect to the scale 35 of the tu-rn rate indicator 31.

The movable element 65 of the display panel also includes a secondpointer part 71 that is read on the scale 37 of the heading indicatorl48 by the helmsmanl to in.

dicate the ordered heading on the heading indicator of the panel. Asindicated, this corresponds tothe head-l ing 336 degrees shown by theset indicator 48. The null position of the pointer 71 correspondsfto theindex or lubber line 38 of the heading indicator 48. In the describedport turn, lthe pointer parts 66 and 71 of the movable element y65 lmovetogether, the first -with respect to the scale 35 and pointer'33 of therate indicator 31, and the second with respect to the -xed index 38 andscale or compass card 37 Iof the heading indicator.

The system functions so that when the actual turn rate ofV the craft `asread on the panel corresponds to the ordered turn rate and the pointer71 of the panel indicator indicates the iordered heading 336 on thecompass card or scale 37 yof indicator 36 as shown, the pull-out pointor time in the maneuver is indicated to the helmsman. The helmsman thenreturns the control stick to itsnull or centered position. In thedescribed maneuver, this operation by the helmsman occurs las the craftturns through a zero azimuth reading on the compass scale of the headingindicator 36. This nulls the input to the servo means 11 lof the systemfrom the output synchro 24 directly controlled by the helmsman. The turnproceeds 'with inputs to the servo means 11 from the turn rate servo 51by Way or lead 62l and from the repeatback synchro 22 by way of lead 23`until the ordered craft heading is reached `without `overshootingwiththe rudder in a streamline condition. As indicated in the panel 32with relation to the ordered heading indicator 48, an angular difference0r error between the related miniers 38 21nd 7.1.,

with respect to the scale 37 indicates the point in the turn at which itis necessary for the helmsman to null the order input to the rudder. Themovement of panel element 65 is dependent on the rate that the craft isactually turning divided by its actual speed. As shown in this regard,meter 68 is connected by lead 78 to the dividing means 72 which isconnected by lead 73 to the output winding of generator 60. The speed Vinput to the dividing means 72 is provided by a suitable craft speedcomputer 714 connected to the rotor of a transmitting synchro 75 byshaft 76. Lead 77 connects the output of synchro 75 to the dividingmeans 72. The output of the dividing means as a ratio of crafts tur-nrate and speed (1li/V) is ,fed the meter 68 at the ldisplay panel 32 ofthe system by way of lead 78. The noted ratio is equivalent to thereciprocal of the turning radius of the craft and is approximately equalto the actual turn rate divided by the maximum turn rate obtainable lfora particular craft speed.

In the improved system heading changes up to 180 turns can be executedat a desired turn rate under control of the helmsman. The initialmovement of the stick or member 26 to locate pointer 33 to eitherstarboard or port of the zero of the scale of ythe turn indicator asdesired and the return movement of the stick or member at the pull-outpoint observed on the display panel 32 controls the operation of thesystem to bring the craft to an ordered heading smoothly and withoutovershootmg.

While the invention has been described in its preferred embodiments, itis to be understood that the words which have been used are Iwords of:description rather than of limitation and that changes within thepurview of the appended claims may be made without departing from thetrue scope and spirit of `the invention in its broader aspects.

What is claimed is:

l. A turn control system -for navigable craft including servo meansoperable to change the heading of the craft having a synchro with arepeatback output; a display panel having a turn rate indicator withrelatively movable scale and pointer parts, a heading indicator havingrelatively movable scale and pointer parts, and a movable element With apart readable on the turn rate indicator and a part readable on theheading indicator; means for ordering a turn rate input to said servomeans including a manually movable member operatively connected to themovable part of the turn rate indicator, and a synchro operativelyconnected to the member providing an output depending on the movement ofthe member from a null position; means for providing an output dependingon the actual turn rate of the craft operatively connected to the servomeans in opposing relation to the turn order input means; and meansresponsive to the `actual turn rate output means operatively -connectedto the movable element of the display panel to move the part thereofreadable on the turn indicator to compare lactual and ordered craft turnrates and move the part thereof readable on the heading indicator' toindicate `the ordered heading on the panel.

2. A turn control system as claimed in claim l, including meansoperatively connected to the actual turn rate output means for adjustingthe system in accordance with the speed of the craft.

3. A t-urn control system as claimed in claim 1, including means forproviding an output in accordance with the speed of the craft, and themeans 'for moving the two part ele-ment o-f said display panel includesmeans for dividing the rate output of the actual `turn rate output meansby the speed output of the speed output means.

4. A system for steering navigable marine craft with a rudder includingservo means operatively connected to the rudder having ya synchro with arepeatback output; a display panel having a turn rate indicator with xedscale and movable pointer parts, a heading indicator having relativelymovable scale Eand pointer parts, and a mov'- able element with a partreadable on the scale of the tur-n rate indicator and a part readable onthe scale of the heading indicator; means ffor ordering the craft toturn including a hel-m control stick connected to the pointer part ofthe turn rate indicator, and a synchro connected to the stick providingan output for said servo means depending on the movement of the stickfrom a null position; means for providing an output depending on theactual turn rate of the `craft operatively connected to the servo meansin opposing relation to the output of the turn order synchro; and meansfor moving `said two part panel element depending on the output of theactual turn rate output means to compare the actual and ordered turnrates on the scale of the turn rate indicator and to indicate theordered heading on the scale of the heading indicator of the panel.

5. A steering system as claimed in claim 4, including means forproviding an output in accordance with the speed of the craft, and meansfor operatively connecting said speed output means to the servo meansand lthe means for moving the two part element of the display panel.

6. A steering system as claimed in claim 5, in which the meansoperatively connecting the rate output means and the two part element ofthe display panel includes means for dividing the output of the rateroutput means by the speed output of the speed output means.

7. In a turn control system for navigable craft having servo meansoperable to change the heading of the craft; a display panel having aturn rate indicator with relatively movable scale and pointer parts, aheading indicator having relatively movable scale and pointer parts, anda movable element with a part readable on the turn rate indicator and apart readable on the heading indicator; means for ordering a turn rateinput to said servo means including a manually movable member connectedto the movable part of the turn rate indicator, and a synchro connectedto the member providing an output depending on the movemtnt of themember from a null position; means for providing an output in accordancewith the turn rate of the craft, means operatively connecting said turnrate output means to the servo means, and means operatively connectingthe two part element of the display panel to the turn rate output means.

8. A turn control system as claimed in claim 7, including meansproviding Van input to the means operatively connecting the two partdisplay element and the turn rate output means in accordance with thespeed of the craft.

9. A turn control system as claimed in claim 7, including meansproviding an input to the means operatively connecting the rate outputmeans to the servo means in accordance -vvith the speed of the craft.

10. In a system for steering navigable marine craft with a rudder havingservo means operatively connected to the rudder; a display panel havingka turn rate indicator with fixed scale and movable pointer parts, aheading indicator with relatively movable compass card and pointerparts, and a movable element with a pant readable on the scale of theturn rate indicator and part readable on the comp-ass card of theheading indicator; means for ordering the craft :to turn including ahelm control stick connected to the movable part of the turn rateindicator, and a synchro connected to the stick providing an output forsaid servo means depending on the movement of the stick from a nullposition; and means providing an output depending on the actual turnrate of the craft operatively connected to the two part movable elementof the display panel and operatively connected to the servo means inopposition to the output of the turn order synchro.

111. In a system for steering navigable craft; a display panel includinga lturn rate indicator with fixed scale and movable pointer parts, aheading indicator with relatively movable scale and pointer parts, and amovable element with a part readable on the scale of the headingindicator and a part readable on the iXed scale of the turn in-Vdicator;V a manuallyVv movable member connected to the movable part ofthe. tur-n rate indicator, and means for prov'ding'an output accordancewith the actual tum rate ofv the. shaft operatively connected to themovable two part element of the display panel.

l2. A steering system as claimed in claim 111, including means providingan output in yaccordance with the speed of the craft, and means foroperating said two part element in accordance withthe output of saidspeed output means.

13. In4 a system for steering navigable craft; a display panel includingla heading indicator having la movable compass card. and a fixedpointer, and a movable element withfa pointer readable on thecompasscard of the heading indicaton-and means for providing lan output inaccordance with the turn ratte and speed of the craft operativelyVconnectedvto the movable element of the display panel.

14. In a system for steering navigable craft; a manually movable turnorder member, a synchro having la rotor operativelyV connected to theorder member providing an output depending on an orderedturn rate; adisplay panel including Ia turn rate indicator having a movable elementoperatively connected to the order member, a heading indicator having amovable element, and a movable double pointer part one of whose pointersis readable on the turn :rate indicator. and the other of Whose pointersis readable. on the heading indicator; means for providing anoutputdepending on the actual turn rate and speed of the craft, means formoving Ithe double pointer part of."

the display panel in accordance with the output of said turn rate :andspeed output` means, and servo means re,

sponsive to .the outputs of. said synchro and turn rate and: speedoutput means operable to change the heading of the craft.

15. A system as claimed in claim 14, in whichtheturn,

rate indicator includes a iixed scale and theone pointerAk of the doublepointer part moves withL respect to thescale, the movable `element ofthe heading indicator is a compass card, and fthe other pointer of thedouble pointerl play panel inraccordance with the actual -turn rate and`speed of the craft.

References Cited in the le of this patent UNITED STATES PATENTS`Henderson Dec. 28, 1926 Koster Aug. 11', 1942

1. A TURN CONTROL SYSTEM FOR NAVIGABLE CRAFT INCLUDING SERVO MEANSOPERABLE TO CHANGE THE HEADING OF THE CRAFT HAVING A SYNCHRO WITH AREPEATBACK OUTPUT; A DISPLAY PANEL HAVING A TURN RATE INDICATOR WITHRELATIVELY MOVABLE SCALE AND POINTER PARTS, A HEADING INDICATOR HAVINGRELATIVELY MOVABLE SCALE AND POINTER PARTS, AND A MOVABLE ELEMENT WITH APART READABLE ON THE TURN RATE INDICATOR AND A PART READABLE ON THEHEADING INDICATOR; MEANS FOR ORDERING A TURN RATE INPUT TO SAID SERVOMEANS INCLUDING A MANUALLY MOVABLE MEMBER OPERATIVELY CONNECTED TO THEMOVABLE PART OF THE TURN RATE INDICATOR, AND A SYNCHRO OPERATIVELYCONNECTED TO THE MEMBER PROVIDING AN OUTPUT DEPENDING ON THE MOVEMENT OFTHE MEMBER FROM A NULL POSITION; MEANS FOR PROVIDING AN OUTPUT DEPENDINGON THE ACTUAL TURN RATE OF THE CRAFT OPERATIVELY CONNECTED TO THE SERVOMEANS IN OPPOSING RELATION TO THE TURN ORDER INPUT MEANS; AND MEANSRESPONSIVE TO THE ACTUAL TURN RATE OUTPUT MEANS OPERATIVELY CONNECTED TOTHE MOVABLE ELEMENT OF THE DISPLAY PANEL TO MOVE THE PART THEREOFREADABLE ON THE TURN INDICATOR TO COMPARE ACTUAL AND ORDERED CRAFT TURNRATES AND MOVE THE PART THEREOF READABLE ON THE HEADING INDICATOR TOINDICATE THE ORDERED HEADING ON THE PANEL.